Updated to asyncoro version 3.1 release.

This version handles peer (network) failures gracefully:
If connections to a peer fail consecutively for MaxConnectionErrors
(defined in disasyncoro module with default value of 10), then the
peer is assumed dead and sending/delivering messages to it
fail immediately.

Reorganized files in to py2 and py3 directories for Python version
2.7+ and 3.1+ respectively, as used in pypi releases.
Reorganized files in to py2 and py3 directories.

Files in py2 are to be used with Python 2.7+ and files in py3
are to be used with Python 3.1+.
Added example to illustrate hotswap feature.

'hotswap' can be used to change coroutine function while application
is running.